The present invention relates to processes for making roll-on antiperspirant compositions. More particularly, it relates to compositions, and processes for making such compositions, with improved compositional stability.
Compositions designed to stop or reduce the flow of human perspiration are well-known in the chemical and cosmetic literature. Such antiperspirant compositions may be applied to the skin by a variety of methods. For example, S. Plechner, "Antiperspirants and Deodorants," 2 Cosmetics, Science and Technology, 373-416 (M. Balsam and E. Sagarin ed. 1972), describes antiperspirant compositions in spray, roll-on, cream, and stick forms. For a variety of reasons, one preferred method of application is as a roll-on.
Roll-on antiperspirants, however, may present certain disadvantages, particularly with respect to cosmetic characteristics. The literature describes many formulations which attempt to provide cosmetically-acceptable roll-on products. A particularly preferred group of roll-on products incorporate volatile silicones. Such compositions are described in U.S. Pat. No. 4,053,581, Pader et al., issued Oct. 11, 1977; U.S. Pat. No. 4,065,564, Miles, Jr., et al., issued Dec. 27, 1977; U.S. Pat. No. 4,073,880, Pader, et al., issued Feb. 14, 1978; and British Patent Application No. 2,018,590, Elmi, et al., published Oct. 24, 1979.
It has been discovered that such compositions that contain mixtures of volatile and non-volatile silicones are subject to compositional instability. In particular, a phenomenon, herein referred to as "creep", takes place wherein the silicone oils in the antiperspirant compositions migrate up the walls of the product container and eventually deposit on the exterior of the container. This problem leads to loss of product materials, poor package aesthetics, and other undesired effects.
It has now been discovered that antiperspirant roll-on compositions, containing volatile and non-volatile silicone oils, have improved compositional stability when such compositions are made by a process in which the product is deaerated prior to filling into a roll-on container. In particular, silicone-containing antiperspirant roll-on compositions, made by the processes of this invention, exhibit reduced incidence of the "creep" phenomenon.